Catalytic reforming without thermal cracking



April 17, 1956 K. M. ELLIOTT CATALYTIC REFORMING WITHOUT THERMAL CRACKING 5 Sheets-Sheet l Filed May l, 1952 v Sgm.

April 17, 1956 K. M. ELLIOTT 2,742,404

CATALYTIC REFORMING WITHOUT THERMAL CRACKING Filed May 1. 1952 5 Sheets-Sheet 2 April 17, 1956 K. M. ELLIOTT CATALYTIC REFORMING WITHOUT THERMAL CRACKING Filed May 1, 1952 5 Sheets-Shee 3 Byj .Zyg

1N VEN TOR.

KENNETH /l/Z ELUUTT April 17, 1956 K. M. ELLIOTT 2,742,404

CATALYTIC REFORMING WITHOUT THERMAL CRACKING Filed May l, 1952 5 Sheets-Sheet 4 Ell-'g' /32/ 4VO/ V 400 r .vl RII IJ l 368 336 sal 3507 345 INVENTOR. 545 5 2 33; KENNETH /W QL/0 rr 5 BY April 17, 1956 CATALYTIC REFORMING WITHOUT THERMAL CRACKING Filed May l, 1952 K. M. ELLIOTT 5 Sheets-Sheet 5 IN V EN TOR. /NNETH M ELL/Orr www United States Patent O 2,742,404` CATALYTIC REFORMING wrrnoU'rjTHnRivrAL g cRAoKrNG Kenneth M. Elliott, .Woodbury, NJQ, assigner toSocony t Mobil OilCompany, Inc., a corporation of New York` ApplicationMay 1, 1952, Serial No.285,482 7 Claims.` (Cl. 19E- 504) to a reactor and a regenerator. In the reactor the reform ing catalyst passes successively through at least two re`- l formingzones. For several reasons in such a reforming heat required'tis supplied by,r the:

operation it is desirable, if not necessary, tolsupply` substantially all of the sensible heat in the vapor feed stream. When it is necessary to reform naphtha under severe conditions, i. e., high temperature level and'relatively high endothermic heat requirement, to make super octane number motor gasolines or aviation blending'stocks ink a single straight through reformerit would'be necessaryl either tolpreheat the charge stock? vapor to a`- temperature which would cause considerable thermal cracking in the preheating" furnaces and transfer lines in otherto provide in the vapor stream suilicient heatfor the reforrning-,4 reaction, or iti would be necessary to` reheattthe reactantf` after partial conversion, i. e.,. subject the charge stockfp to an intermediate heating step, and then? re-ineet` the charge stockinto the reformer to complete'the conversion.

lt has been found that` the foregoing undesirable alternatives-cau be avoided by operating a single reactor with the feed distributed between.' an upper reformingy zone and a lower reformingzone'through` which4 the catalyst' passes successively, or two reactors through which the catalyst passes successively under such conditions that the vapor feed is heated to a temperaturerabove' the reforming temperature but below atternperature at which substantial thermal cracking occurs, the heat capacity of the vapor stream is controlling of the temperature in the rst reforming zone which the catalysteuters, the

vapor passingito the said rst zone carries with'- it more heat than isV required for the degree of` reforming desiredin saidrrst zone'and the excess heat inrthe vapor supplied to said tirst zone is transferred to the catalyst flowing 2 i t i, `1 therethrough, andthe transferred` heat carriedf byv the catalyst into theV second reforming'zone,` where itl-tis used to help effect the severer" refrmingreaction desired" therein. Accordinglymlie'more severe reforming operation is conducted in the second zone which the catalyst enters whileA the heat for the" total` reforming issupplied by `the vapor VfeedA withoutk thermalv cracking thereof and without the necessity for reheating` thetchargetduring its conversion. u j

` Accordingly, it is anobject ofi the present'tinvention to providel a method of reforming non-aromatici and substantially non-aromatic mixturesof hydrocarbons in which substantially all of the heat required for the reaction is supplied in the charge mixture vapors without substantial `thermal cracking of the charge stock and Without reheating of the charge stock during conversion. It is another objecttof: the-present` invention to provide ajmethod of t reforming non-aromatic or` substantially no nfaromatic mixtures of' hydrocarbons'in whicli cessively through twoireformingzones. The.vaporspassingintolthe first retorminggzonewhich the catalyst jehters carry with. them more, heat than is required `fori the: degree of" reforming desired in saidffiirstzdrie andthe excessfheat iu the vapor supplied-1to'sa'idairst4 zones-is transferred: tof the catalyst flowing therethrough;A audi the' transferred heaticarried. by. the catalyst'intothc: secondreforlmjing `zone where it helps to' effect the reforming; reartidndei i siredtherein. Othen objectsfand-` advantages:-wfill` become t apparent'from' the'followingdiscussion taken in' conjuncp tion with the drawings in` which p t Figure 1 is a schematic ow diagrarnof:a-rtworeform ingzone split-feed reactor; t

Figure 2 isa diagrammatic illustrationY of` twolreactors inserieswhich canreplaee the single reactor of Figure l;

Figure 3 is a diagrammatic illustrationlot a' multifeed` inlet reactor which can replace the reactor of 1Figure.v wherein the4 volume of the twocatalyst bedstforming-the' two reforming zones can be `varied whilst simultaneously controlling the distributionA of chargef stock"y tdtthe t'woj reforming zones so forrne'di` t n t Figure 4r is a-diagrammatic,illustrationfof a sitiglefre actor with a plurality of charge mixture inlets=`whereby the' depth-of the catalyst beds in the twovrefortningtzoiies caribe complementally varied"whilstsimultaneously,controlling thet'dist'ribution'of two charge'stocksbetween the two reforming.zones?` so formedgfaudV n ,d I Figure 5 isya `diagrammatic illustration of areae'tfor having two reforming zonesin'whiclithe tantinet/recycle gas to-charge stoclecanbe varied;` In general, themethod oireformingafnonaaromatcor substantially nonatornatc` mixture offhydrocarbonsA such t as a straight-run or virgin naphtha, a: cracked--naplitha or a mixture of straightrun and cracked naphthas,. as`

listes arable r.

Htenfed Apr. 17, 1956 rrlecafaiyst Heuristics t t cent Amount of Heat Re vuirenleut of lower zone supplie 3 TABLE I Operating ranges 1 The total heat transferred from the vapors entering the upper zone to the bottom zone ls calculated by the following equation:

where,

E ls etciency, percent.

. Ti is temperature of catalyst leaving upper zone, F. (enters lower Reactor Broad Preferred r zone) J T2 is temperature ot catalyst entering upper zone, F.

Ts is temperature of catalyst leaving lower zone, F. Vapor Inlet Temp., Minimum F., above av- 5 The amount of lower zone heat requirement supplied by the vapors erage temp. required in upper zone 20 40 passing through the upper zone, percent can be calculated from the Reactor Pressure, p. s. i. a 15-600 1GO-300 following equation: Ges Recycle Ratio: (HT) (E) Mols Gas/Mols Naphtha 2-15 ll-l() X== Mois Hydrogen/Moisivzpiiiha-- i-s 2-5 10 HR Space Velocity, Average ln Reactor 1-6. 0 0.5-2.0 Whew'. Vapor flow to upper zone, percent 9.525 85-50 HT 1S @at transfer as calculated above; Catalyst Bed above Reactor met' Volume E is utilization eiciency as calculated above; percent 80-20 70.30 HR is heat requirement of the lower zone, BTU/lb vapor, and

Heat Transferred from Upper Zone vapors to X is percent of lower zone heat requirement supplied by vapors passing Alower zone, B. t. u./lb. vapor to lower zono 1. 4. 0-125 through the Dpef Zone- Utillzaticn eciency of heat transferred to v Alowertzoiel, percent 2 1 t h: ico-2o iocao 10 Space velocity, as used herein, is the number of volnioun o ower zone ea requ einen supplied by upper zone vapors, pei-conta 5 2ll urnes of liquid charge stock passing through the reactor vapor Sgam Heat ospaeiry/osiaiyststream n r per hour per volume of catalyst holdup in the reactor. Heat @801W (upper zone) 0' 40 0'92 As will become manifest hereinafter, the space velocities T ,tu o F Kiln 600 1 400 700 1 OOO m both zones are not always equal and iii fact usually .empara re, Pressure, p. s. i. a is-eoo -35 20 are dlffefelt- The ratio of vapor stream heat capacity to catalyst stream heat capacity, i. e., VSHC/CSHC is the numerical value of the ratio of the product of the pounds of vapors per hour and the specific heat thereof to the pounds of 'liTjis heat transfer, B. t. u./lb. of vapor Vto lower zone. Distribution 9 the VaPfS in conhtfoued amounts to .15 temperatur@ 0f catalyst leaving upper Zne- F- the two zones is obtained by throttling devices restrictirs temperature of catalyst entering upper zone, F. h f f t f h @Op 1s specic heat of vapors B.t. u.l1b./ F. lng t e 0W O r6 orma e rom t e two Zones.

i Ris Vapor Stream Heat Capacity/Catalyst Stream Heat Capacity The advantage] of the present method of reforming Ol` uppl ZODB.

lrlllsjlbsliifvpor tgiiipper zofi1i1/lbts-t0fvelporotloil'ei` zone. b 30 employing a split-bed, split-110W reactor over the once u ZB. 011 e C GDCY O BB. lflJlS el'le 0 OWBI ZORG can 0 s calculated from the lollowlug equatlon: through single bed reactor is recognized immediately f upon study of thc data presented in Table 1I.

TABLE II E'ect of VSHC/CSHC on the octane number ofthe gasoline from cach reforming zone Feed Stock: Virgin Venezuelan Naphtha, B. R. 200-40D F. Octane Number:

F-l (clear) F-l +3 cc. TEL/gal Catalyst: Chromia-Alumlna Beads comprising at least mol percent a Catalyst in upper zone, percent of total Vapor to upper zone, percent o total.. Vapor to lower zone, percent of total.. Average Operating Conditions in the Reactor.

Vapor Inlet Temperature, F..

Catalyst Inlet Temperature, F Gas Recycle Ratio:

Mols Gas/Mols Naphtha (Sp. heat. 0.89 B. t. u./1b./ F.)

Mols Hydroxgcn/Mols Naphtha VSHO/OBHO* for upper zone 25 Reforming Zone Upper Lower Upper Lower Upper Lower Upper Lower Upper Lower Liquid Space Velocity, V./Hr./V Vapor Inlet Temperature, F... Vapor Outlet Temperature, F. .Average Temperature, F

Endothermic Heat of Reaction, B.

. 67 68 Catalyst Inlet Temperature, F.. 975 l, 975 l,

CatalystA Outlet Temperature. F Sensible Heat in Catalyst to Upper Zone abov Av. Temp. as percent of Upper Zone Heat Requirement Catalyst to Naphtha weight ratio Catalyst to Vapor Weight ratio Octane N umher:

ser

through upper zone, B. t. u./lb. vapor to lower zone. Utilization Eiciency of Heat transferred to lower zo pors passing throng upper zone, percent Vapor Inlet Temperature required to obtain lower zone number in a conventional reactor, F Gasoline Yield from conventional operation to produce oc number of lower zone product, volume percent of charge. Gasoline yield increase due to elimination of thermal reform volume percent charge Negligible 0.8 1.8 5.2 1.3

.'.VSHO/CSHC is the ratio of the product of the pounds of vapor entering the first reforming zone and the specific heat thereof to the product of the pounds o! catalyst entering the first reforming zone and the specic heat thereof.

errance While anin'creased yieldof 0 8` pery cent to 5129er cent, in ffable llfsliov'v the efectlofl'th'e.distribution of charge percentagewise. i appearssmau, `ierepresems an increased alglgwYlgil/afrct mmm?, Ofabout 12010 abut 780 barrels per stream of the distribution of the vapors in catalyst beds of equal day on a 15,000 BPSD umt 5 volumes upon the yield of high octane rating gasoline.

The data presented in Table II established thefeect In Table IV are presented-data-showing the effect of TABLE III Feed Stock: Virgin Venezuelan Naphtha, B. R. 20W-400 F. Octane Number: F-l (clear) F1l-3 cc. TEL/gal Catalyst: Chromia-Alumina Beads compris! Average Operating Conditions inthe Reactor:

Pressure, p. s. i. a Average Space Velocity, liquid Vapor Inlet Temperature, F Vapor Specific Heat, B. t. u./lb`./F Gas Recycle Ratio:

Mols Gas/Mols Naphtha Mols Hydrogen/Mols N aphtha Reforming Zone Upper Lower Upper Lower `Upper'y Lower VSHG/CSHC* 0.9 Volume of Catalyst, percent of total.. 50` Volume of Vapore, percent of total. l `15 Vapor Inlet Temperature, F 1,050 Vapor Outlet Temperature. F 1. 008 Catalyst Inlet Temperature; FL 1,050 Catalyst Outlet Temperature, F 1,008 Average Temperature, F 1, 016" Liquid Space Velocity, V./Hr./V 0121 Endothermc Heat of Reaction, B. ti u./lb. Vapor 834 Vapor Inlet;` Temperature required to obtain same octane number ln a conve 1, 1,201A Gasoline Yield. Volume percent chargeto zone 63.5 Goline Yield, Conventional Operation Volume percent charge 53. Increased Yield dueto elimination of vThermal Reforming l0.5 Catalyst to'Vapor Ratio by weight 3. 81 Octane Number: I

F-l (clear) 103.0`

F-1+3.cc. TEL/gal 107.0` Sensible Heat in Catalyst entering upper zone above average temperat zone as percent of upper zone heatrequirem'cnt 4 S 0. 4 0 Total Heat transferred to lower zonet from vapors passing through `B. t. 11./lb. vapor through lower zone 21 31 f 70 Utilization ediciency. of heat transferred-to lower zone, pereen 82 77` 60 Amount of'heat required lnlower zone supplied by vapors pass 25 31 51 *VSHC/CSHC is the ratio of the product'of e pounds oivapor entering therstreforming'zone and the speeic'beat thereof to the-product 'of the pounds of catalyst entering the nrst reforming 'zone' andthe specific heat thereof. i

of the VSHC/CSHC upon the octane number of the, the split of the catalyst bedf-betweentworeforming.zones gasoline producedin each reforming zone. The data Egg? theoctne mung fthegaSOlmPTOdUCedm each' TABLE IV` Feed Stock: Virgin-VenezuelanNaphthm B; R. 200-400 F; Octane Number:

F-l (clear) F-1+3 ec. TEL/g Catalyst: Cliromia-Alum ds comprising at least 70 mol Average Operating Conditions in Reactor:

. Pressurep. s. i. a

Average Space Velocity, liquid- Vapor Inlet Temperature, f F Vapor Specific Heat; B. t. u./lb./ Cas Recycle Ratio:

Mols Gas/MolsNaphtha Mols Hydrogen/Mols N aphtha CaseIII Reforming Zone 'Upper `Lower Upper Lower Upper Lower. `Catalyst; Bed, volume percent'of total 30 50 50 30 70 VSHC/CSHC* 24 3. G 2.4 3 2 4 Catalyst to Nophtha weight ratio- 2 43 1.62 2. 43 1 62 2 43 Volume of total vapors, percent' 40 60A 4l) 40 Liquid Space Velocity, 'v'./lln/V.. 1l 1 0. 93 0. 84 O. 56 1. 40 0. 40 Vapor LnletfTemperature, F.. I 1, 05()i 1,050 1,050 1, 050A Y 1,05Il Vapor Outlet Temperature, F. 95 996 957 el 964 991` Average Temperature, F

Catalyst Inlet;Y Temperature, f F.. Catalyst Outlet Temperature, `F Catalyst to Vapor weight ratio o, Octane Number: Y

F-l (clear) 95. 5 87. 5 98. D S4. 0` 99.3 F-1I-3 cc. TEL/gal l 101. 5 96. 5 103. 5' 94.0 104 5 Gasoline Yield, Volume percent oi charge to zone. 80, 0 86, 2 75.0 88. 3 71 3 Vapor Inlet Temperature required to obtain same oc n conventional operation, F. 1, 065 1, 085 1, 095 Gasoline Yieid from conventional operation to produce same octane rating, volume percent 79:4 86 2 73,2 88 3 'f'. S Increased Yield due toelimiuatlon of Thermal Reforming, percent 0. 6 1,8 3. 5 Sensible in Catalyst entering upper zone above overaav npperzooe temperature as percent 0f upper zone beat requirement 2 0 1. 7 0 Total Heat transferred to lower zone from vapors ente pper zone, B. t. u./lb. vapor to lower 26 zonei 26 26 Utilization Eflciency ofleat transferred to lpwer zol percent 77 80 84 Amount of heat required in lower zone'supplxed byvapors passing through upper zone, percent.-. 29 29 29 *VSHC/CSHC is theratlo o theproduct ofthe pounds ot vaporlenteringthetirst retrmingzoiean the speoitcfleat'thereot to the produetfotitlie` pounds of catalyst entering the first reforming zone and the specific heat thereof.

8 Gas-tight valve 12 is then closed, valves 17, 22 and 23 closed and valve 19 opened whereby pressuring gas such as recycle gas is introduced into pressuring chamber 13 A The data presented in Table IV show that, with other variables such as VSHC/CSHC, vapor split and overall space velocity constant, the volume of catalyst in the reforming zone of greater severity has a marked effect through lines 61 and 4S until the pressure therein is at upon the octane rating and yield of gasoline from that least that of reactor 24 and preferably about 5-10 p. s. i. a. zone. higher. Gas-tight valve 14 then is opened and the cata- The data presented in Table V show the effect of lyst flows into surge chamber 104. Valve 14 is closed `VSHC/CSHC on the octane rating of the gasoline pro and valve 23 then 1s opened and the residual gas in duced when different charge stocks are treated in the pressure chamber 13 is vented to a flare, not shown.

two reforming zones; the more refractory stock being 10 This completes the cycle. charged to the zone of greater severity. The catalyst ilows from surge chamber 104 into and TABLE V Feed Stocks:

(1) Feed to Upper Zone-Blend of 55 volume percent California Virgin Naphtha, and 45 volume percent Cracked Gasoline from coklng a California reslduum. B. R. 225-400 F., Octane No.: F-1(elear) 65, F-l -l- 3 ce. TEL/gal. 76. Weight percent sulfur 0.60.

(2) Feed to Lower Zone: Virgin Venezuelan Naphthe. B. R, 20T-400 F., Octane No. Fl(clear) 39, F-l 3 cc. TEL/gal. 61. Weight percent sulfur 0.04

Catalyst: Chrolnia-Alumina Beads comprising 70 mol perlxent alumina, balance chrornia Average Operating Conditions:

Pressure, p. s. i. a Average Space Velocity, liquid. Vapor Specinc Heat, B. t. u./1b./ F 0 8g Gas Recycle Ratio:

Mols Gas/Mols Naphtha 0.6 Mols Hydrogen/Mols Naphtha 0.3

VSHC/CSHC upper zone Upper Lower Upper Lower Upper Lower Reforming Zone Volume of catalyst as percent of total 50 Volume of total vapors as percent of total. 50

Space Velocity, V./Hr./V 0. 7

Catalyst to Naphtha weight rat .90

Vapor Inlet Temperature, F. Vapor Outlet Temperature, F Average Zone Temperature, F Catalyst Inlet Temperature, T. Catalyst Outlet Temperature, F. Octane Number:

F-l (clear) Fei -l- 3 cc. TEL/ga Sulfur in Product, Weight percent Vapor Inlet Temperature required to obtain same octane number in conventional Endothermic Heat of Reaction, B. t. u./lb. vapor Gasoline Yield, volume percent of charge to zone Gasoline Yield, Conventional operation volume percent o charge... Increased gasoline yield due to elimination of thermal reforming, percent Sensible Heat in catalyst entering upper zone above upper zone average temperatur heat requirement of upper zone, percent Total Heat Transferred to lower zone from vapors passing through upper zone,

to lower zone Utilization Edicicncy o t transferred te lower zone, percent Amount of Heat required in lower zone supplied by vapors passing through upper Z VSHC/CSHC is the ratio of the product 0f the pounds of vapor entering the first reforming zone and the specific heat thereof to the product of the pounds of catalyst entering the tlrst reforming zone und the specific heat thereof.

The foregoing and Similar results can be Obtained by downwardly through reactor 24 as a substantially comreforming the non-aromatic and/or substantially non- Pact Column fSt Clnacting the uPWfndly OWng VaPOlS aromatic mixtures of hydrocarbons in the manner il- 0f the Charge mixture and then flowing COncnffently With iustrated in the drawings. Referring to `Figure 1, the 50 the vaporsofthe chars@ mixture During passeeethroush course of the catalyst through the reactor and kiln will the reactor, the Cl'llyst 'UECOIneS Spent and Contaminated be followed iirst and then the course of the charge mixwith il 031430113060115 dePOS- The Spent Ca'dlyst leaves ture will be followed through the reactor and auxilianI the reactor through a catalyst flow-control device such as equipmentthrottle valve 25. When operating at pressures in excess Active catalyst at a temperature of about 100 to about 55 0f atmOSpheric and when the kiln is Operating at a pres- 1100911. and preferably at about 400 to about 800 F. sure below that of thc reactor, it is preferred to transfer is accumulated in reactor catalyst feed bin 11. Since the reactor is shown as operating at 190 p. s. i. a. although means, whereby the spent catalyst is transported to the the reactor pressure can be l5600 p. s. i. a. and preferkiln, by any suitable means whereby solid particles can ably 1D0-300 p. s. i. a., a reactor sealing and catalyst 60 be transferred from a zone of high pressure to a zone of transfer means is necessary. Any suitable device for less pressure. The catalyst ows through catalyst ow transferring particles from a zone of one pressure to a control means 25 into surge tank 2d from which it is rezone of higher pressure can be used. For the purpose moved in any suitable manner as by a pressure lock. of illustration, a pressure lock formed between gas-tight The pressure loci; formed between gas-tight valves 27 valves 12 and 14 and including pressuring chamber 13 65 and 28 includes depressnring chamber 29 and operates in will be described. The pressure lock operates in a cyclic a cyclic manner similar to the pressuring lock at the top manner as follows: of the reactor previously described hereinbefore.` Thus,

With gas-tight valves 12 and 14 closed, pressure charnwith gastight valves 27 and 2S closed, depressuring chamber 13 is purged with an inert and/ or non-ilammable gas ber 29 is purged with an inert and/or non-ilammable gas such as ue gas drawn from a source, not shown, through 70 such as flue gas. The purge gas is drawn 'from a source pipes 15 and 16 under control of valve 17 with valve 19 not shown through pipes 30 and 31 under the control of closed and vented to a are, not shown, through lines valve 32 with valve 33 closed and vented to a are, not 20 and 21 under control of valves 22 with valve 23 closed. shown, through pipes 34 and 35 with valve 36 open and Valve 12 is opened and catalyst llows into pressuring valve 37 closed. Valves 32 and 36 are closed and prescharnber 13 to fill the chamber to a predetermined level. 75 suring gas such as recycle gas is drawn through pipes 38 the spent catalyst from the reactor to a catalyst transfer 2111x131" with valve 33 open andintroduced into depressuring chamber 29 until the pressure therein` is. that of the surge tank 26. Valve 33`is closed and gas-tight vallve27v opened. Catalyst ows, into depressuring chamber 29-to fill itto4 a pre-determined level. Gas-tight valve 27 is closed,v `valve 37 opened andthe gas in depressuring cham.- ber 29. vented to-a are `until the pressure in chamber 29 is. reduced to. that of the kiln` or, regenerator. Gas-tight va1ve.28 then is openedv and` the` catalyst ows into. surgeA chamber S and thence into chute 39. This completes the cycle.` p

The spent catalyst flows along chute 39to any suitable` catalyst transfer meanssuitable for transporting the spent catalyst to the kiln or regenerator. Suitablecatalyst transfer meansv include gas-lifts and the like, elevators, etc.

For. I nlrpose-of discussion, an` elevator 40 is illustrated.

Thecatalyst flows along-*chute 39 to the boot 41 of bucket elevator4 40;V more. fully described in U. S. Patent No. 2,409,596. p The catalyst in elevator boot 41 is picked up by the elevatorbucketsrV andraised to theV elevator head 42 where it is discharged into chute 43 along which ittlows` to spent catalyst hopperl 44` atop ofkiln or regenerator 45.

Kiln or regenerator` 45 isof any suitable type wherein thecarbonaceouswdeposit on` the spent catalyst can be burned oif=in1a stream of combustion` supporting gas, such as air, at temperatures ofI about 600-l400 and preferably at about 700l000 F. at pressures of 15-600 preferably -35 p. s. i. a. A suitable kiln is described `more fully in U. S. PatentvNo.` 2,469,332. However, the kiln 45 "illustratedis provided with cooling coilsy represented by 46 through ,whichwater from drum 47 by means of pipes 48: and 49: is.-y passed and returned to stream drum 47 through pipe 50. i

Thetspentfcatalystpasses downwardly from hopper 44 througliikiln-45 totchute 5'1 by means ofwhch the regen erated .or reactivatedfcatalyst is carried to a suitable catalystvtransfer-idevice, such as a gas-lift or the like, or as illustrated, a` bucket elevator 52 by means of which the active catalyst is raised tothe reactor catalyst feed bin 11 ready for another cycle through the reactor and kiln.

Returning nowto thereactor; the course of the reactant and"`refc' rmatewillA be'- followed. A mixture of` hydrocarbons containinghydrocarbons convertibleto aromatic hydrocarbons such as a petroleum naphtha is drawn froma sourcenot shown through line 106 and introduced into absorber 107 wherein the naphtha or charge stock contactsv the make gas. Absorber 107 is of any. type suitable forgas-liquid contact and stripping the gas of light hydrocarbons. The make gas is produced in the reactor during tire` reforming reaction.` Through contact with the net gas make in absorber 107, the charge stock strips light hydrocarbonsfrorn'thev gas and leaves absorber 107 'through line 53 and passes through heat exchanger 54 where it is in indirect heatexchange with the reformate; From heat exchanger S4, the charge stock passes by line 55 to charge stock heater 56 wherein the temperature of the charge stock is raised to a temperature above the reaction temperature but below that ofthermal reforming or crack-` ing. The temperature ofthe charge stock will usually be about 850 to about 1080 F. and preferably about 960- l060 F. The charge stock leaves heater 56 through line 57.`

The recycle gas isrseparated from the condensed hydro-` carbons. of the .reformatein separator 59, ,leaves separator 59S by way, of pipe 60 to pipe 61 where the net gas produced is passed through line` 62.to absorber 107.` After contact with the chargestockin `absorber 107, as describedhereinbefore, the stripped gas passes out ofabsorber. 107. throughpipe 63 to .fuel gasholder 64.

` The balance ofthe `recyclevgas in pipe 61 ilowsthercthrough to pipefGS, passes through heat exchanger 66 wherein it is in indirect heat exchange with reformate and4 passcsthroughtpipe'l. to recycle. gas heaterS.

In recycle gas heater 68 the recycle gas is heated to a temperature suchA that when. mixed with the' charge stock to form a charge mixture, thecharge mixture enters. the reactor 24 at a temperature f about 850`1080 F. and preferably about` 960-1060 F. To attain this end' the recycle gas is heated4 in furnace 68`to about l000 to about 1300 F.

`The heated recycle gas leaves heater 68 through pipe 69. Heated charge stock inline 57 and heated recycle gas. inppe 69 are mixed in line 70 by regulation of valves 71. and 72 respectively to give a charge mixture containing charge stock and recycle gas in the mol ratio of 1-15 mols recycle gas to l molof charge stock and preferably about 4 to about 10 mols of recycle gas p er 1 mol of chargestock. The4 average molecular weight of the charge stockis determined in theusual manner from the ASTM distillation curve.

When the charge stock is to be reformed in the presence of hydrogen it s preferredto use a recycle gas containing about 25 per cent to.` about 80 per cent, and` preferably about 35 per cent to about 60 per cent hydrogen, balance C1 to Ce hydrocarbons. Such a hydrogen-containing recycle gas is mixed with` the charge stockI in the ratio of about l to about 8, preferably about 2 to about 5 mols of hydrogenrper mol of charge stock. The average molec- `ular Weight of the charge stock being determined in the being intermediate the endsof reactor 24 and at about the mid-point thereof. The location of the charge mixture inlet at about themid-point of reactor 24 divides theV catalyst bed in reactor 24 into two beds of approximately equal volume; an upper bed U and a lower bed L. In order to introduce into ther upper bed U more heat than isrequired for the degree of` reforming desired in bedU and to provide for removal of the excess heat by the catalyst passing into bed Lit is necessary torregulate and control the distribution of the vapors ofthe charge mixture-between the two beds. This` control and regulation is obtained by throttling devices 73 and 74 in reformate outlet lines 75 and176.

Throttling devices 73 and 74 are of any suitable type whereby the volume of vapors passing therethrough can be regulated. Throttle valves of conventional designhave given satisfactory results. By means of th'rottling devices 73 and 74, the distribution of charge mixture vapors can be controlled dependent upon the degree of severity of reforming required in bothreforming zones and in such a manner as to supply substantially all of the heat required in both zones for the reforming` action. Accordingly, the ratio of the product of the pounds of charge mixture entering the reactor per hour and its specific heat, i. e., vapor stream heat capacity, to the product of the pounds p of catalyst enteringthe reactor per hour, and its specific heat, i. e., catalyst stream heat capacity, is held within the limits of about 200 to about 0.5 and preferably within thelimits of about 40 to about l. In general, with the aforesaid ratio of vapor stream heat capacity (VSHC) to catalyst stream heat` capacity (CSHC) in the upper reforming zone held within the limits of about 40 to about 0.7 and preferably about 25 to` about 0.9, about 95 per centto about 25 per cent, and preferably about 85 per cent to about 50 per cent of the vapors of the charge mixture will be passed upwardly 'and counter-currently to the catalystpassing. through catalyst bed U and the balance downwardly and concurrentlywith the.` catalyst passing throughbed L by setting valves 73 and 74 to produce the distribution` of charge mixture vapors between beds Ud andL in accordance with the exigenciesof the particularcircumstances; also be regulated by catalyst flow-control regulator 25.

As .previouslystated, catalyst rate can The average space velocity, i. e., liquid volume of charge stock er hour per volume of catalyst in the reactor is about 0.1 to about 6.0 and preferably about 0.5 to about 2.0. However, as those skilled in the art will immediately recognize, the space velocity in the reforming zones U and L will vary dependent upon the division of the total catalyst volume and upon the distribution of the vapors of charge mixture between beds U and L. In general, however, when the same charge stock is being treated in both reforming zones, the space velocity in zone L preferably is lower than in zone U While for two different charge stocks when the less refractory charge stock is treated in zone L, the space velocity in the bottom zone can be as much as 3 times that of the other charge stock in zone U but will usually be lower in Zone L than in zone U.

te reiormate and gas produced during the reaction together with recycle gas leave zone 'U through line 75 under control of throttling device '73 while the reformate, make gas and recycle gas leave zone L through line '76 under control of throttling device 7d. The effluents from both zones mix in line '77. It is to be -obseiyed at this point that when operating, to produce gasolines of different octane ratings the reformates are kept separate and that when desired, as described in my co-pending application Serial No. 285,483, tiled this same-day, the make gas f and recycle gas from each zone can be kept separate and a part or all of one bled olf. Such alternatives are illustrated in Figures 2, 3 and 4,

The mixed e'liluents from zones U and L pass through line 77 into heat exchanger 66 giving up some of the heat in the etiluents to the recycle gas by indirect heat exchange. From heat exchanges 66, the mixed ellluent passes through line 73 to indirect heat exchanger 79 wherein some heat is given up by the mixed effluent to the Water entering the heat exchanger 79 from pipe 4 by means oi pipe $5. The water leaves heat exchanger '79 through pipe S and flows to steam drum 257. The mixed eluent leaves indirect heat exchanger 79 through line S0 and enters indirect heat exchanger 54 wherein the mixed cluent gives up heat to the incoming charge stock. The mixed eiiiuent leaves heat exchanger S-i by line Si and passes through cooler S2. From cooler 32 the mixed effluent passes through line 83 to liquid-gas separator 84.

ln separator 84 the make gas and recycle gas rise therein and leave separator 84 by pipe 108. The condensed hydrocarbons leave separator S4 by line 8S. The malte gas and recycle gas are compressed in gas compressor 56 to a pressure sufcient that with the usual losses a pressure of about l to l500 p. s. i. a. preferably about U-300 p. s. a. is maintained in reactor 2d. The f compressed gas leaves the compressor through pipe 37 and is mixed with the condensed hydrocarbons from separator d4 in line Sti. The mixture of compressed gas and condensed hydrocarbons passes through litre il? into cooler 90 and through line all into recycle gas separator 59.

The recycle gas leaves separator through pipe 6u. The condensed hydrocarbons leave separator 59 through line 92 and enters depropanizer 93.

ln depropanizer 93, which is of conventional design, the C1 to C3 hydrocarbons and absorbed recycle gas separate 'from the gasoline and leave through pipe 94. The gas tlows through pipe 9d to pipe e3 where it is mixed with gas from absorber 107,. r[he mixed gases pass through pipe 63 to fuel gas storage or holder oli.

rThe depropanized reformatc leaves depropanizer 93 by line 95 and primary re-run tower Sie of any suitable design in which a substantial portion of the gasoline in the reformate is dashed, overhead as a gasoline containing substantially no polymer. rThe flashed gasoline containing no substantial amount of polymer leaves re-run tower 95 through line 97 and passes to storage lill. The bottoms from re-run tower 916 passes through. line 98 to secondary re-run tower 99. in secondary re-run tower, which is of any suitable type, there is a separation of gasoline of required endpoint from polymer. The gasoline passes from secondary re-run tower 99 through line lill) to gasoline storage 101. The polymer leaves secondary re-run tower 99 through line 102 and passes to polymer storage 103.

On some light charge stocks, the stabilizer or deptopanizer bottoms can be used for motor gasoline blending without further processing other than caustic washing. However, when charging naphthas of 400 F. or higher endpoint, o-r when charging naphthas containing substantial amounts of cracked materials, the stabilizer bottoms contain a small amount, about l per cent, of polymer which is substantially all aromatic compounds boiling in the range of 400 to 700 F.

Referring now to Figure 2. Two reactors are illustrated in Figure 2 which can replace reactor 24 of Figure land can be used in conjunction with the auxiliary equipment illustrated in Figure l in accordance with the principles of the present invention. Therefore, the use of the reactors illustrated in Figure l will bcdescribed Without a discussion of the treatment of the reactor etiluents since that has been discussed in conjunction with the discussion of Figure l.

Active catalyst is accumulated in reactor catalyst feed bin 111 and is introduced into reactor 124 through-any suitable device whereby solid particles can be transferred from a zone at a given pressure to a Zone at higher pressure. Such a reactor sealing and catalyst transfer device is illustrated in Figure 2 as a pressuring lock formed between gas-tight valves 112 and 114.

The reactor sealing and catalyst transfer device operates in a cyclic manner and comprises gas-tight valves 112 and 11d and pressuring chamber 113. The cycle is as follows: With gas-tight valves .112 and 114 closed, the pressuring chamber 1113 is purged with an inert and/or non-'flammable gas such as flue gas introduced from a source not shown through pipes 115 and 116 with valve 119 closed and valve 117 open. The purge is vented to a liare not shown through pipes 120 and 121 with valve 123 closed and valve 122 open. After purging, gas-tight valve 112 is opened and catalyst introduced into pressuring chamber 113 until the chamber is lilled to a pre,- determined level. Gas-tight valvet112 is then closed. Valves 117 and 122 are closed and valve 1.19 opened.y A pressuring gas such as recycle gas drawn from a source not shown through pipes 165, 118 and 116 is introduced into pressuring chamber 113 until the pressure therein is at least as high as that in reactors 124 and 124a. Gas-tight valve 114 then is opened and the catalyst ilows into surge chamber 204. Valve 114 is closed and valve 123 opened and the residual gas in chamber 113 'vented to a iiare not shown through pipe 120y until the pressure in chamber 113L is as low as that of reactor catalyst feed bin lill. This completes the cycle.

The catalyst .ows from surge chamber 204 downwardly in. reactor 124 as a substantially compact column counter-current to the upwardly liowing vapors of the charge mixture introduced into reactor 124 through line 170 and its associated distributor.

The catalyst leaves reactor 124 carrying the excess heat transmitted thereto from the vapors of the charge mixture and passes through conduit 200 into reactor 12d-a as a substantially compact column. In the top of reactor 124g the downwardly 'llowing catalyst encounters the vapors of charge mixture introduced into reactor .l2-41a through line 170a and its associated distributor. The catalyst and vapors of the charge mixture flow downwardly concurrently through reactor 124e, the catalyst leaving the reactor and passing through catalyst ilow control device 125 and surge tank 126'to a reactor sealing aud catalyst transfer means of any type suitable for transferring solid particles from'a zone of given pressure to a zone of lower pressure.

ln Figure 2 the aforesaid reactor sealing and catalyst transfer device is illustrated as a pressure lock similar to that at the top of reactor 124 and operating in a.

arranca.

13 similar cyclic manner as follows:V With gas-tight valves 127`and 128 closed, depressuringfchamben129 is-purged with an inert` and/or non-liammable purge gas such aslluegasdrawnfrom a source not shownthrough, pipe troduced through pipes 131 and, 138 into. chamber 129 until the` pressure therein is, about equal tothat insurge tank 126. Valve 133 is closed and gasftight valve 127fis.

opened and catalyst flows from tank 126intodepressuring chamber` 129 to ill chamber 129 to` a` predetermined level. Gas-tight valve 127 is closed and valve 136 open.

and.` the pressuring gas, in chamber129ventedto` a Hare not shown through pipes 134. and 135; Gas-tghtvalvev 123 is then opened and the catalyst flows out of charnber 129 into surge chamber 205` and thence to chute 139. This completes the cycle. i

The catalyst which has become deactivated or spent through contact with the vapors of the charge mixture or mixtures in passage through reactors 124" and 124e flows through chute 139 to any suitable catalyst transfer means such as a gas-lift or the like or an elevator as `illustratedvin Figure 1 whereby the spentl catalyst is transferredto a kiln of suitable design wherein the spent catalyst is reactivated by burning E the carbonaceous deposit thereon in a stream of.' combustion supporting gas such as air. a

The catalyst passes through the kiln in which the carbonaceous deactivating deposit is burned olf' to provide reactivated catalyst and is transferred to reactor catalyst feed bin 111 ready to begin another cycle through the reactors 124 and 124a. i

For simplicity of` illustration and description,` the reactors 124 and 124a have been shown in Figure 2 as treating the same charge stock. Those skilled in the art` will recognize that two different charge stocks can be treated, one in vreactor124'- andthe other'in reactor 124a. A charge stock is drawn from'a source not shown, passes through an absorber and` heat exchangerv as illustrated in Figure 2 and enters furnace 156 -throughfline 155. The

charge stock,` say anaphtha, is heated n-furnace156 to a temperature below a thermal reforming; temperature.

The heated charge stock leaves furnace 1515` through line` 157 and1 passes into line 170 under controli off'valve172.

Recycle gasdrawn from a source not shown through line 165 is heated in furnace 168 to a temperature such that when passed through pipe 169.1 and` mixed with charge stock in line 170 in the ratio-of about-'1` to about l mols, preferably about 2 to about 5mols of recycle gas per mol of charge stock, the` temperature of thel charge mixture so formed will besufficiently high to supply a preponderant portion of the heatgrequired,l for reforming in both zones, such that the ratio ofvapor stream heat capacity to catalyststream heatcapacityY in reactor 124 shall be abountr400.7 andpreferablyabout O.9 and the temperature of the charge mixtureV isabout 850 F. tofabout1080 F; andpreferably about 96011?. toV about 1060. E;

The charge mixture in line 170 then;` passes. through lines 170? and 17641 and, the associated;rdistributorsnot' shown into reactors 124 and. 124a. In Figure 2 the catalyst volumes in both reactors 124v and 124a are shown as about equal. TheV distributiony of the vapors of charge mixture between reactors124 and 124:1. is.

controlled and regulated in amanner similar to that'` employed in conjunction with reactor- 24.` That` is` to say, the distribution of charge'mixture to` reactors 124 and-124a is.` controlled and regulated by throttlng:I de-` ure l in combination with` the eiuent fromreactor 1240 whenthere is nolneed to keep. the two reformates separate and no needftokecp the two. gasmixtures separate.` However,l under some conditionshigher octane, gasoline` is. produced in one reactor than in the other. in addition, under some conditions it is. advantageous to keepf the gaseous eluents separate. Such is; provided. for in` Figure 2 as illustrated. That is to say, the-eiliuent from` reactor 124 llows4 through line 175, throttling device 173, various heat exchangersand cooler 182 to separator 184. In separator 184 the uucondensed gases leave the separa-tor, by wayv .of pipe while a portion or all ot' the'gasis-bled ofi through pipe 162to fuel gas storage or a are not. shown under control of valve 190. The condensedhydrocarbons are drawn olf. from separator. 184 through line 192. and passed to suitable stabilizingand re-run` towers-or. similar fractionating-and treating opcrations as shown in Figure l.

The chargemixture vapors enter reactor 124e Athrough line er andits` associated distributor and pass down wardly concurrently with the downwardly flowing substantial compact column of reforming catalyst.

The eiluent i.` e., reformate, make gas and recycle gasfleavereactor 124g through line 176 under` control and regulation of throttling device 174. The eluent passesthrough the various heat exchangers illustrated in Figure. 1 to cooler 132e and` separator 184m In separator 184e the u'ncondensed` gases leave through` pipe 160:." andrninwith the uncondensedgas from reactor 124 in pipe` 191 ready for useras recycle gas. All or a: portion of the gases .leaving separator 18461 can be bled to` fuel gas storage or aflare, not. shown, as required` or desired through pipe `162:1 under control of valve. 19,0(1.

The. condensed hydrocarbons in separator 134g are passe-tls through line'192a to stabilizing, fractionating` or other equipment` as shown in Figure l.

In Figure. 3 is shown in aschematic marinera reactor. 224 provided Withi a plurality of charge.` mixture inlets whereby the complementary volumes of two reforming zones can bevariedover` a relatively wide range. Thus, whenthe. vapors of the charge mixture enter reactor 224 through manifold branch zz and its associated distributor; not shown, the reactor is divided into two reforming zones wherein the upper zone has a catalyst volume of 25 percenty of the total while the lower zone has a catalyst volume 75fper` cent of the total.. Similarly, when the vapors of the charge` mixture` enter reactor 224. through manifold branch d and itsv associated distributor not shown, the reactor is divided into two reforming zones. wherein. the upper zone has a` catalyst volume of 75 per cent of the total while'the lower zone has a catalyst volume of 25' per cent of the, total. Those skilled. in the art` will understand that reactor 224 can be provided withas many vapor inlets as thestructure permits and is considereddesirable.

vices173 and 174 which can'be throttle valves, of conf i ventional design. Throttling devices 173 and 174 are a Valves-:212.and 214 are gas-tight valves and 213. is a.

pressuring.,chamber.` Purge gas is introduced intochamber 213 through pipes 215 and 216 under control4 of.

` valve-217 and vented through pipes 220 and 221 under control of valve 222. Pressuring gas is drawn from pipe 265 through pipes 218 and 216 under control of valve 219 and introduced into chamber 213. Pressuring gas is vented from chamber 213 through pipe 220 under control of valve 223.

Catalyst enters surge chamber 304 from gas-tight valve 214 and passes downwardly as a substantially compact column into reactor 224 and through reactor 224 countercurrent to the charge mixture vapors in that portion of the reactor above the charge mixture inlet and concurrently with the charge mixture vapors in that portion below the charge mixture inlet to leave reactor 224 through catalyst flow control device 225, surge tank 226 and a reactor sealing and solid particle transfer device whereby the particles of spent or deactivated catalyst are transferred from a. zone of high pressure to a zone of lower pressure. The reactor sealing and solid particle transfer means illustrated in Figure 3 comprises a depressuring lock similar to that shown in Figure l formed by gas-tight valves 227 and 223 and depressuring chamber 229. The depressuring lock operates on a cycle similar to that described in conjunction with Figure l.

Purge gas is introduced into cie-pressuring chamber 229 through pipes 230 and 231 under control of valve 232 and vented to a. flare not shown through pipes 234 and 235 under contro-l of valve 236. Pressuring gas such as recycle gas is drawn through pipes 23S and 231 under control of valve 233 and introduced into chamber 229. The pressuring gas is vented to a are, not shown, through pipe 234 under control of valve 237.

The spent catalyst iiows through valve 228 into surge tank 3dS and thence to chute 239 and thence to a catalyst transfer device not shown whereby it is transferred to a kiln or regenerator, not shown, such as illustrated in Figure l or of any other suitable type whereby the deactivating carbonaceous deposit on the spent catalyst can be burned off in a stream of combustion supporting gas such as air. The reactivated catalyst is then returned to reactor catalyst feed bin or hopper 211.

Charge stock such as a petroleum naphtha in line 255 is heated in furnace 256 to a temperature above the reforming temperature but below the thermal reforming temperature. Recycle gas in pipe 24S enters furnace 26S wherein it is heated to a temperature such that when mixed with charge stock in the ratio of 1 to l5, preferably about 4 to 10 mols of recycle gas per mol of naphtha, the charge mixture vapors will have a ternperature of about 850 to about 1080 F. and preferably about 960 to about l060 F. and about 20 to about 200 F. above the average reactor temperature. The

heated recycle gas passes through pipe 269 under control of valve 271 to line 270. Heated charge stock leaves the furnace through line 257 under control of valve 272 and enters line 270 Where it is mixed with heated recycle gas.

Line 27d acts as a manifold from which spaced apart branches 11, b, c and d conduct the charge mixturc to spaced apart associated distributors not shown. Manifold branches a, "b,' c and "d are provided with valves 27%y 27011, 270e and 2706!. The charge mixture is introduced into the reactor through any one of the branches ze "b, c and d or others, not shown. A portion of the vapors of the charge mixture iows upwardly counter-current to the downwardly flowing substantially compact column of catalyst in the zone above the inlet through which the charge mixture is introduced into the reactor and downwardly concurrent with the downwardly flowing substantially compact column of catalyst through the zone below the charge mixture inlet.

The distribution of charge mixture between the zone above the charge mixture inlet and the zone below the charge mixture inlet is regulate-d and controlled by throttling devices 273 and 274 in etiluent lines 275 and 276 respectively. Throttling devices 273 and 274 serve the purpose of the throttle valves 73 and 74 in Figure l.

The euent from the upper zone leaves. reactor 224 through line 275 passes through various heat exchangers and finally condenser 282.

The eiuent from the lower zones leaves reactor 224 through line 276 passes through various heat exchangers and finally condenser 282a.

Those skilled in the art will understand that, when the gasolines from both reforming zones in reactor 224 are of substantially the same octane rating and it is not necessary nor desired to discard a part of all of the gas from one zone, the etiluents from both Zones can be combined as in Figure l and treated together.

As illustrated in Figure 3 the effluent from the two zones are treated separately in separators 234 and 284a.

" The condensed hydrocarbons from separators 284 and 23411. leave the separators through lines 292 and 292a respectively to fractionating equipment and storage such as illustrated in Figure l.

The uncondenser vapors in separators 254 and 28411 leave the separators through lines 260 and 260:1 respectively. When desired, a portion or all of the gases leaving either separator 284 or 284a can be bled to fuel, or a are, not shown, through pipes 262 and 262e under control of valves 290 and 290:1.

Figure 4 provides a schematic illustration of the application of the principles of the present invention to the treatment of two charge stocks. The course of the catalyst through the reactor 324 and the kiln, not shown, is the same as more fully discussed in conjunction with Figure l. The fractionation and stabilization of the reformate is carried out in a manner similar to that described hereinbefore. Thus, active catalyst is stored in reactor catalyst feed bin 311 and is intro-duced into reactor 324 through any suitable reactor sealing and catalyst transfer means whereby solid particles in a zone of given pressure are transferred to a zone of higher pressure. Such a sealing and catalyst transfer means is illustrated in Figure 4 as a lock system operating in a cyclic manner as more fully described in conjunction with Figure l. That is to say, the catalyst transfer means comprises gas-tight valves 312 and 314 and pressuring chamber 313. A non-ammable and/or inert gas such as flue gas is used to purge pressuring chamber 313. The purge gas is drawn from a source not shown through pipes 315 and 316 under control of valve 317 into chamber 313 and vented therefrom through pipes 320 land 321 underl control of valve 322, valves 319 and 323 being closed. After purging chamber 313 catalyst is admitted thereto until chamber 3ll3 is filled to` a pre-determined level. Chamber 313 is then pressurized with gas-tight valves 312 and 314 closed and valves 317, 322 and 323 closed. The pressuring gas is usually recycle gas drawn from a source not shown through pipes 348, 36S, 318 and 316 and introduced into chamber 313 until the pressure therein is at least that of reactor 324; Valve 314 is then opened and the catalyst flows into .surgel chamber 344. Valve 314 is closed and the cycle completed.

The catalyst flows from surge chamber 344 downwardly through reactor 324 as a substantially compact column counter-current to the upwardly flowing reactant vapors in the upper zone (defined hereinafter) and concurrently with the reactant vapors in the lower zone (defined hereinafter). During its passage through the reforming zones, the catalyst becomes contaminated with a carbonaceous deposit which. decreases the catalyst activity and the catalyst is then denominated spent catalyst.

The spent catalyst leaves the reactor 324 through catalyst 'liow control device 325. Catalyst dow control device 325 is of any suitable type such as a throttling Valve.-

From the catalyst flow control device the catalyst passes into surge tank. 326 and thence to a reactor sealing andl solid particle transfer means whereby the catalyst particles can` bc transferred from a Zone of given pressure to a zone of lower pressure.. Of course, when the regenerator 17 or ldln is operating at the same pressure as the reactor, such a catalyst transfer means usually is not'required The catalyst transfermeans illustrated inra schematic manner in Figure 4 is a depressuring lock such as illus"- trated in Figure 1 and discussed in more detail` in conjunction therewith.

The catalyst transfer means comprisesga'satight valves 327' and 328 and depressuring chamber 329. The catalyst transfer means operates cyclically as follows: Purge, pressurize, lill, depressurize, empty. Purge gas is drawn from a; source not shown through pipes 330 and 331 with valve 333 closed. and valve332l opent Thepiirge is vented to a flare not shown throughipipe-s334 and`335 with vali/e336 open and valve 337 closed. The chamber 329` is pressurized with recycle gas tc' the pressure existingin .surge tank 326` drawn from'a 'sourcer not shown" through pipes 348,4 338i and 3311 with valves 3321, 336 and 337 closed and valve` 333` open, gas-tight valves 327 and 328 being closed; Chamber 329`is `filled withcatalystl toapreedetermined? level by opening gas-tight valvc1327. After chamber 329 has been filled` to a' pre-determined level,- gastight valve 327 is closed and the pressure in chamber 329 reduced to that of the kiln, not shown, by venting the gas1 therein to a llare not shown through pipe 334under control of valve 337. Gas-tight valve 328i is thenopened anduthe catalyst` flows in'tofsurgeL chamber 345 and thence to chute 339'. The cycle isthen completed;

'lhc catalyst flows along chute-339f'to any suitable cat# alyst transfer device, not` shown, whereby the' catalyst is transferred: to the kilnorregenerator.

rlhe kilriis of: any suitablertlypewherebythe.carbonaceous deposit isrburned olli-in aA stream of combustion supportingngaslsuch as air.. By removal of thecarbonaceous deposit the` catallysris'V reactivated. The catalystleaves the kiln as'. activatedscatalyst and is transferredto reactor' catalystfeedl` bin 311l1byr any suitablecatalyst transfer device such as agas-lift or the like'pan' elevatoretc.

Before` discussing the pathofthe reactants through' the reactor, it is believed welly to discuss'the formation of upper and` lower' reforming zones` in reactor 3241 The upper'reformin'gizone is rthat portion of thereactor above the particular` pair of charge mixture inlets and' associated'` distributors, notshown, being used atlanytime. The lower reforming: Zonekis that'po'rtionfof" thereactor below theA particular `pair ofi` charge mixture inlets and associated distributors,4 not showngcbeing used ata'nyiparticular time-.r Thus, as illustrated, react'on324is` provided with a: plurality of spacedapa'rt pairs ofcha'rge' mixture inlets, tir-403, b-404, c-4tl5 and d40'6\,andotler asso-- ciatedV distributorsn'ot: shown. The pairsof charge mixture inlets. and associated distributors not shown divide reactor 324 into an upper'zone'of 25 per cent ofthe cat# alyst4 volume and a lower zone of 751p"er e'entof` the catalystvolume when pair ne403`is1 used.` 'Iheupperrefornif ingfzoneinf reactor. 3'24zis 7215er centofthe cata'lyst'v'ol. urne and the lower reforming zone isl 281y per"c'e'ntof"`the" catalyst volume when.` charge mixture inletpair #406 and the associatedr distributors isuseda The other pairs'divide the: reactorinto upper reforming-2 zonesofBO per cent and 4-7 per cent ot the catalyst volume* with corresponding lower reforming-zones of..70 perrcent4 and-53 per"cent In i treating two charge stocksirr accordance with" the principles of the present` invention,4 one charge stook'is drawn from au sourcenot` shown', through an absorber when desired andA various heat` exchangers and'l introducedinto furnace 356by meanseofline. 355. In furnace 35o-the charge stock is `heatedy to" a temperature below thethermal` reforming temperature; The heatedl` chargestock leaves` the furnace through line1357 anclspasses into line 370.

Recycle gas; which,` when: the reforming reaction is carried out" in the presence of hydrogen? comprises aboutz 25-per cent toabout' 80 perl? cent,x preferably: about `35 percent toiabout 60 pen'centhydnogen, balanceCiftoCi` hydrocarbons. is` drawn fronta source; notyshown;

through pipes 348 and 349" and lieatetiy furnace 35S to" a temperature such that when mixed with the charge stock` in the' ratio of about l` to alioutl lmols, preferably about 4 to about l0 mols of gas f per mol of chargestock, provides a charge mixture carrying into the" upper reforming zone an amount of heatin excess of that required in the upper zone for the reforming reaction taking place therein. p

A second charge stock is drawn through line 400 from a source, not shown, and heated in furnace 401 to a temperature below `the thermal reforming temperature. The heated second charge stock leaves furnace 401by means of line 402. i i

The heated recycle` gas leaves furnace 36S by pipe 369 and passes through pipe 394 under control of valve 395 to line 370 whererit is mixed with heated charge stock l in the ratio `set forth hereinbefore to form` a charge mixture 1. i i p The heated recycle gas `Yin pipe 369 passes through pipe 393 under control of valve 371 :and mixes `with charge stock 2 in lines 4&2 to forni chargeV mixture 2. It is to be noted that recycle gas `can be mixed with both charge stocks in the `same or diherent molar ratios Within the limits of about l to about. l5, preferably about 4 to about l0 mols of Whenreforming in the presence of hydrogen, the recycle gas` comprises' about 25 per cent to about 80 per cent, preferably about 35 per cent to about 60 per cent `hydrogen, balance Ci to C6 hydrocarbons and is mixed with `the two charge stock'sin the same or different molar ratios within the limits-of about l to about'S, preferably about 2 to about 5 mols of hydrogen per mol of charge stock. The` average molecularweight of' the charge stocks being determined in theusual manner from the ASTM distillation curve. t

The chargemixture' 1` ini linef370 enters reactor 324 through one of the branches a; b, c, or d of line 370 under the control' of valves 3794i; 37017, 370C or 37th] respectively dependent upon' the octane rating required in the gasoline produced in the upper reforming zone, the refractoriness of' the charge stock` and similar' considerations.

Whichever inlet a; b,`.c` or ci which .is selected for introduction of charge mixture 1 into reactor 324 the i other member of the pair isfusedto introduce charge mixture 2 into the reactor. Thus, for the purpose of illustrationandv description, the i chargel'mixtureswill be described as entering reactor 324 through charge mixture inlets sci and"405fand `thel associated distributors not shown'.`

The` distributors associated with the pairs of charge mixture inlets are of any suitable type whereby the chargefnnxtu-rlecanfbe distributed over substantially the whole.` cross-section of t' the reactor.

Charge mixture l in line 370 passes through branch or chargemixture inlet c and `its distributor.` The vapors thereof flow upwardly through the portiony of the reactor above inlet c countercurrent to the downwardly flowing substantial-ly compactrcolurnn of catalyst and out of the upper` reforming zone through line 375 under control of-l throttlingmeans 373 of any suitable type whereby the volume of reformate and.` associated gases can be controlled andl regulated. Such` control and regulationofithe effluent frornthel upper reforming zone controls the quantity of charge mixture l which `passes through the .upper reforming zone.-

Charge mixture 2- enters reactor 324 through branch orfc'hargemixture inlet 405 and its distributor not shown of any suitable type whereby the charge mixture is distributed over substantially `the' entire cross-section of reactor 324; The vapors of charge mixture 2 ow downwardly concurrent witlr the downwardly flowing substantially compactcolumn ofcatalyst. The effluent from the lower reforming zone leaves the lower reforming zonefthrough-line376 under control-ofthrottling device 374` which `is ofany suitabletype-such as a` throttle i valve gas per mol of naphtha.

whereby the volume of eflluent passing through line 376 is regulated and thereby the quantity of charge mixture passing through the lower reforming zone is regulated.

The euent from the upper zone and that from the lower zone can be mixed when gasolines of substantially the same octane rating are produced. The mixed eiuents then be passed through the various heat exchangers and thence to stabilizing and fractionating equipment such as illustrated in Figure l.

When producing gasolines of different octane ratings the eiluents are kept separate. Thus, the elhuent from the upper reforming zone passes through line 375 and various heat exchangers to cooler 332 from which the cooled effluent passes through line 2533 to liquid gas separator 384.

The condensed hydrocarbons in separator are withdrawn through line 392 and passed to suitable stabilizing and `sactz?onating equipment.

The gases separated in separator 1584 leave through pipe 369 to recompression and recycle. When it is desired, the .whole or a part of the gases from separator 384 can be vented to a liars or fuel storage through pipe 362 under control of valve 3%.

in a similar manner the effluent from the lower reforming zone leaves reactor' 324 through line 376 under control of throttling device 374 and passes through various heat exchangers to cooler 332:1. The cooled eluent passes through line 383m to separator 384e. In separator 3tl4a the condensed hydrocarbons separate and are withdrawn through 392s to stabilizing and fractionating equipment such as illustrated in Figure l.

The gases separated in separator 384e pass through pipe 36951 to recompression and recycle with or without contact with incoming charge stock. When desired, a.

portion or all of the gases from separator 384:1 can be vented to a flare or fuel gas storage through pipe 362a under control of valve 39ml.

In Figure is provided a schematic representation of a multi-inlet and consequently multi-bed or multi-zone reactor in a simplified form for ease of representation and discussion. Those skilled in the art will appreciate that while the reactor as represented is shown with only two inlets positioned at approximately the vertical midpoint of the reactor sufficient inlet pairs of groups can be provided to permit division of the catalyst bed as illustrated in Figures 3 and 4.

The reactor illustrated in Figure 5 provides a means for operating each reforming zone of the reactor at a different recycle ratio simultaneously. At high catalyst to oil ratios it is often desirable and under some conditions, such as need for operation at low coke lay-down levels, necessary to be able to maintain a higher recycle gas to charge stock ratio in one reforming zone than in the other.

Since the passage of the reforming catalyst successively through the reforming zones and thence to the kiln or regenerator has been described in the discussions of Figures l, 3 and 4 and since the passage of the reforming catalyst through the reactor illustrated in Figure 5 is the same, it is believed unnecessary to repeat the description provided hereinbefore and only necessary to discuss and describe the ow of the charge stock and recycle gas through the reactor and associated aftertreatment.

Thus a charge stoclt comprising a mixture of hydrocarbons containing hydrocarbons convertible to aromatic hydrocarbons such as a naphtha is drawn through line 455 to furnace 456. The charge stock is heated in furnace 456 to a temperature below a thermal reforming temperature. Gf course, two charge stocks could be treated simultaneously as shown in Figure 4 but to avoid prolixity and to simplify the following discussion and description the treatment of only one charge stock will be given. The heated charge stock at at least a catalytic reforming temperature and below a thermal reforming temperature 2@ leaves furnace 456 via line 457 under control of valve 472 and enters line 47 t).

Recycle gas, which when reforming a charge stock in the presence of hydrogen, comprises about 25 to about 80 and preferably about 35 to about 60 per cent hydrogen and the balance Ci and Cs hydrocarbons, is drawn through pipe 467 and heated in furnace 463 to a temperature such that when mixed with the charge stock to provide a charge mixture the vapors of which enter the reactor at a temperature at least 20 F. and preferably at least 443 F. above the average temperature in the upper reforming zone and supplies at least per cent of the required heat of reaction. The heated recycle gas leaves furnace 468 via pipe 469.

Two methods of supplying diiferent amounts of recycle gas to the two reforming zones can be employed. For example, the charge stock can be split as by passing charge stock through lines 470 and 507 under control of valves 472 and 503 respectively and introducing recycle gas into each portion of charge stock through pipes 509 and 504 under control of valves 471 and 506 respectively or the charge stock can be introduced through one line 470 or 5&7 admixed with recycle gas therein and additional recycle gas, introduced into the other reforming zone through the other inlet.

For example, heated charge stock can be passed through lines 470 and 507 and heated recycle gas admixed with the charge stock in both lines 470 and 507 to provide charge mixtures having different ratios of recycle gas to charge stock of about 1 to 15 mols of gas to 1 mol of charge stock by admitting heated recycle gas from pipe 5ti9 into line 470 in an amount to provide a charge mixture having, for example, a recycle gas to charge stock ratio of say about 6 to about 8 mols of recycle gas to l mol of charge stock and admitting heated recycle gas from pipe 504 into line 507 in an amount to provide a charge mixture having, for example, a recycle gas to charge mixture ratio of about l0 to l2. On the other hand, heated charge stock can be passed through line 597 only, heated recycle gas admitted from pipe 504 in an amount to provide a charge mixture having, for example, a recycle gas to charge mixture ratio of about 4 to 6 mols recycle gas to one mol of charge stock and sufficient heated recycle gas admitted to the lower reforming zone through pipe 509 and line 470 and the associated distributor to raise the recycle gas to charge stock ratio from the existing 4 to 6 mols of recycle gas per mol of charge stock to say 10 to l2 mols of recycle gas per mol of charge stock.

Mixing of the vapors of the upper and lower reforming zones and consequent vitiation of the regulation of the recycle gas to charge mixture ratios at the inlets is obviated by means of the throttling devices 473 and 474 which are of any suitable type whereby control of the volume of effluent passing therethrough is obtained and maintained such as throttling valves.

The reformate from the upper zone U leaves the reactor 424 via line 475 under control of throttling device 473. The reformate from the lower zone L leaves the reactor 424 through line 476 under control of throttling device 474. When the reformates from both zones are of the same octane rating, the reformates are mixed in line 477 passed through various heat exchangers, as illustrated in Figure l to cooler 482. Thence through line 490 to separator 484 from which the uncondensed euent passes through pipe 485, a compressor not shown and pipe 487 to line 489 where the compressed uncondensed effluent is mixed with the condensed ellluent and passed to the separator, stabilizer and fractionators illustrated in Figure 1.

When the reformates of the upper and lower reforming zones are of dilferent octane ratings, the euent from upper zone U passes through line 483 to heat exchangers, cooler, etc., such as shown in Figure l. The etuent from lower zone L under these conditions passes through line., 483m tothe. heat exchangers; cooler stabilizer ete. shown in Bgure 1.

The foregoing discussion has been descriptive of a method operating a-` split-How reactor to provide an upper and a; lower reforming zone; in which the sensible heat content of the catalyst stream entering. thev upper reforming zone above the average temperature inthe upper zone is not more than about 25 per cent ofthe heat requirement of the upper reforming zone; the vapor inlet temperature is at least F. and preferably at least 40 F. above the average temperature in the upper reforming zone; when the same charge stock is fed to both the upper and lower reforming zones, the space velocity in the lowerzone is not greater than the space velocity in the upper zone; and when two different charge stocks are treated simultaneously and the less refractory stock is fed to the lower zone, the space velocity in the lower zone can be as much as 3 times the space veloctiy in the upper zone. Accordingly, the present invention provides a method of reforming a mixture of hydrocarbons containing hydrocarbons convertible to aromatic hydrocarbons such as virgin petroleum naphtha, cracked naphtha, and mixtures of straight run and cracked naphtha simultaneously at two different severities or two different charge stocks at two different severities over the same catalyst to obtain two gasoline products of different octane numbers comprising passing a reforming catalyst successively through two reforming zones, passing reactant vapors counter-current to catalyst flow in the first reforming zone and concurrent to catalyst flow in the second reforming zone at rates such that the ratio of the vapor stream heat capacity to the catalyst stream heat capacity ratio is about 0.7 to about 40 and preferably about 0.9 to about in the first reforming zone, heating the charge stock and recycle gas to a temperature such that the charge mixture entering the iirst reforming zone supplies at least 75 per cent of the required heat of reaction in the top zone and the charge mixture entering the second reforming zone carries less than the heat required for the more severe reforming reaction occurring therein, the temperature in the second reforming zone automatically being higher, the charge mixture entering the rst reforming zone carrying an amount of heat in excess of that required for the reaction occurring therein and said excess heat being transferred to the catalyst contact in said first reforming zone and carried into said second reforming zone by said catalyst, and the space velocity in the two reforming zones being controlled so that the reforming reaction is more severe in the second reforming zone than in the first reforming zone.

I claim:

l. A method of reforming hydrocarbons wherein particle-form solid reforming catalyst ows downwardly as a substantially compact column successively through at least two reforming zones under reforming conditions of temperature and pressure and then through a regenerator in a cyclic manner, wherein the catalyst bed in the first reforming zone is about 20 to about 80 per cent of the total volume of catalyst in both reforming p zones, wherein a heated charge mixture comprising a substantially completely vaporized charge stock containing hydrocarbons to be reformed and recycle gas is introduced into each reforming zone wherein about 25 to about 95 per cent of the total charge mixture treated in both zones is introduced into said first reforming zone, wherein a major portion of the required heat of reaction in all of said reforming zones is supplied by said charge mixtures without substantial thermal cracking of said charge stock, wherein the ratio of the vapor stream heat capacity of charge mixtures entering said reforming zones to the catalyst stream heat capacity is about 0.5 to about 200, wherein the average space velocity of said charge stock for all of said reforming zones is about 0.1 to about 6.0 and wherein at least one charge stock is heated to a temperature higher than the average reaction. temperature in' the 'rst' reforming zone but below,u a temperature at which substantial thermallcracking occurs, recycle gas is heated to a. temperature of about 1.000 to about- 1300L F., mixing said heated charge stock. and said heated` recycle gasto provide a heated charge mixture having a temperature of at least 850 F. and at least 20 F. abovethe average temperature in said first reforming zone, introducing particleform` solid reforming catalyst into the.v first of said reforming zones, flowing said particle-form` reforming catalyst downwardly as a substantially compact column through said rst reforming zone, regulating the temperature and amount of particle-form solid reforming catalyst introduced into said first reforming zone to supply not more than about 25 per cent of the required heat of reaction therein, introducing said charge mixture into the bottom of said first reforming zone, flowing said charge mixture upwardly through said first reforming zone, regulating the amount and temperature of charge mixture introduced into said rst reforming zone to supply heat in excess of the balance of the heat required therein and not supplied by said catalyst and between about 2-5 and 95 per cent of the total4 charge mixture introduced into all of said reforming zones, contacting said charge mixture with said reforming catalyst to reform hydrocarbons and to transfer at least a portion of the charge mixture heat to said catalyst column to supply more than about 5 per cent of the heat required in the second reforming zone whereby said reforming catalyst leaves said lirst reforming zone yat a higher temperature than the reforming catalyst inlet temperature of said first reforming zone, withdrawing heated reforming catalyst from the bottom of said first reforming zone, introducing said withdrawn heated reforming catalyst into the top of a second reforming zone without any substantial loss of sensible heat, introducing heated charge mixture into the top of said second reforming zone, iiowing said heated Withdrawn reforming catalyst as a substantially compact column downwardly through said second reforming zone, owing said heated charge mixture downwardly in contact with said catalyst column whereby heat transferred from said charge mixture to said catalyst in said first reforming zone supplies more than 5 per cent of the heat required in said second zone, withdrawing vapors from the top of said first reforming zone as a iirst efliuent, withdrawing vapors from the bottom of said second reforming zone as a second eftiuent, separating liquid hydrocarbons in said first and second effluents from gases, recycling said separated gases to said reforming zones, withdrawing reforming catalyst from the bottom of said second reforming zone, regenerating said withdrawn catalyst, recycling said regenerated catalyst to said first reforming zone.

2. The method of reforming hydrocarbons as set forth and described in claim l wherein the charge stock is a petroleum fraction.

3. The method of reforming hydrocarbons as set forth and described in claim 1 wherein the charge stock is petroleum naphtha and the recycle gas contains at least 25 per cent hydrogen.

4. The method of reforming hydrocarbons as set forth and described in claim l wherein the charge stock introduced into the second reforming zone is not the same charge stock which is introduced into the first reforming zone and the recycle gas contains at least 25 per cent hydrogen.

5. The method of reforming hydrocarbons as set forth and described in claim l wherein the same petroleum naphtha charge stock is introduced into both reforming zones, the space velocity in the second reforming zone is not greater than the space velocity in the rst reforming zone and the recycle gas contains at least 25 per cent hydrogen.

6. The method of reforming hydrocarbons as set forth and described in claim l wherein the petroleum naphtha i 23 charge stock treated in the second reforming zone is less refractory than the charge stock treated in the irst reforming Zone, the space velocity in the second reforming zone is up to three times the space velocity in the rst reforming Zone and the recycle gas contains at least 25 per cent hydrogen.

7. The method of reforming hydrocarbons as set forth and described in claimy 1 wherein the volume of catalyst in the rst reforming zone is greater than the volume of catalyst in the second reforming zone, the same volume of charge mixture is passed through both reforming zones 24 and the recycle gas contains at least 25 per cent hydrogen.

References Cited in the le of this patent UNITED STATES PATENTS Eastwood Apr. 22, 1947 

1. A METHOD OF REFORMING HYDROCARBONS WHEREIN PARTICLES-FORM SOLID REFORMING CATALYST FLOWS DOWNWARDLY AS A SBUSTANTIALLY COMPACT COLUMN SUCCESSIVELY THROUGH AT LEAST TWO REFORMING ZONES UNDER REFORMING CONDITIONS OF TEMPERATURE AND PRESSURE SAND THEN THROUGH A REGENERATOR IN A CYCLIC MANNER, WHEREIN THE CATALYST BED IN THE FIRST REFORMING ZONE IS ABOUT 20 TO ABOUT 80 PER CENT OF THE TOTAL VOLUME OF CATALYST IN BOTH REFORMING ZONES, WHEREIN A HEATED CHARGE MIXTURE COMPRISING A SUBSTANTIALLY COMPLETELY VAPORIZED CHARGE STOCK CONTAINING HYDROCARBONS TO BE REFORMED AND RECYCLE GAS IS INTRODUCED INTO EACH REFORMING ZONE WHEREIN ABOUT 25 TO ABOUT 95 PER CENT OF THE TOTAL CHARGE MIXTURE TREATED IN BOTH ZONES IS INTRODUCED INTO SAID FIRST REFORMING ZONE, WHEREIN A MAJOR PORTION OF THE REQUIRED HEAT OF REACTION IN ALL OF SAID REFORMING ZONES IS SUPPLIED BY SAID CHARGE MIXTURES WITHOUT SUBSTANTIAL THERMAL CRACKING OF SAID CHARGE STOCK, WHEREIN THE RATIO OF THE VAPOR STREAM HEAT CAPACITY OF CHARGE MIXTURES ENTERING SAID REFORMING ZONES TO THE CATALYST STREAM HEAT CAPACITY IS ABOUT 0.5 TO ABOUT 200, WHEREIN THE AVERAGE SPACE VELOCITY OF SAID CHARGE STOCK FOR ALL OF SAID REFORMING ZONES IS ABOUT 0.1 TO ABOUT 6.0 AND WHEREIN AT LEAST ONE CHARGE STOCK IS HEATED TO A TEMPERATURE HIGHER THAN THE AVERAGE REACTION TEMPERATURE IN THE FIRST REFORMING ZONE BUT BELOW A TEMPERATURE AT WHICH SUBSTANTIAL THERMAL CRACKING OCCURS, RECYCLE GAS IS HEATED TO A TEMPERATURE OF ABOUT 1000* TO ABOUT 1300* F., MIXING SAID HEATED CHARGE STOCK AND SAID HEATED RECYCLE GAS TO PROVIDE A HEATED CHARGE MIXTURE HAVING A TEMPERATURE OF AT LEAST 850* F. AND AT LEAST 20* F. ABOVE THE AVERAGE TEMPERATURE IN SAID FIRST REFORMING ZONE, INTRODUCING PARTICLEFROM SOLID REFORMING CATALYST INTO THE FIRST OF SAID REFORMING ZONES, FLOWING SAID PARTICLE-FORM REFORMING CATALYST DOWNWARDLY AS A SUBSTANTIALLY COMPACT COLUMN THROUGH SAID FIRST REFORMING ZONE, REGULATING THE TEMPERATURE AND AMOUNT OF PARTICLE-FORM SOLID REFORMING CATALYST INTRODUCED INTO SAID FIRST REFORMING ZONE TO SUPPLY NOT MORE THAN ABOUT 25 PER CENT OF THE REQUIRED HEAT OF REACTION THEREIN, INTRODUCING SAID CHARGE MIXTURE INTO THE BOTTOM OF SAID FIRST REFORMING ZONE, FLOWING SAID CHARGE MIXTURE UPWARDLY THROUGH SAID FIRST REFORMING ZONE, REGULATING THE AMOUNT AND TEMPERATURE OF CHARGE 